Replaceable jaw insert for pipe wrenches



Oct'. 27, 1953 w. J. JOHNSON ETAL REPLACEABLE JAW INSERT vFOR PIPE wRENcHEs 2 Sheets-Sheet l Filed July 14, 1950 oct. 27, 1953 Filed July 14, 1950 *a ,.Hllllllilmmlm j? v f NIW.

w. J. JOHNSON ETAL.

REPLACEABLE JAW INSERT FOR PIPE WRENCHES 2 Sheets-Sheet 2 INVENToR. Walzer Joizn'z LM/Www@ Patented Oct. Z7, 1953 REPLACEABLE J AW INSERT FOR PIPE WRENCHES Walter J. Johnson, Buff Eggertsville, N. Y.,

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alo, and Carl G. Ertell, gnors to J. H. Williams & Co., Buffalo, N. Y., a corporation of New York Application July 14, 1950, Serial No. 173,904

(Cl. fil- 186) 2 Claims.

The present invention relates to wrenches, and more particularly to light Weight pipe wrenches having strengths, and more particularly yield points, which compare favorably with malleable iron and steel pipe wrenches of corresponding size.

Pipe wrenches of the class described, and particularly those of the larger sizes, are heavy to carry and handle and are dangerous to use on piping through which combustible or inflammable iluids flow because of the re and explosion hazard from sparks which might be given oil during the use or accidental dropping of a wrench. To overcome the aforementioned shortcomings inherent in malleable iron and steel pipe wrenches, it has been proposed to make pipe wrenches from aluminum and other light weight alloys and to provide such wrenches with hard,

wear-resisting jaw inserts and also to make such Wrenches from other non-ferrous alloys possessing requisite strength and spark resistance, such as beryllium copper alloys.

Wrenches made from aluminum alloys in part overcame the shortcomings of the malleable iron and steel wrenches but they possessed an inherent weakness of having yield points under proof load and ultimate strengths which were too low and hence frequently failed in use by breaking at the movable jaw in proximity to the juncture of the jaw and the jaw shank or at the handle just behind the frame through which the movable jaw shank extends. Wrenches made from berylliumcopper alloys,.on the other hand, although possessing requisite yield point and strength, weigh about three times as much and cost more than three times as much as aluminum'alloywrenches of corresponding size.

An object of the present invention is to provide `a light Weight pipewrench having a yield point under proof load which compares favorably with malleable iron and steel pipe wrenches.

Another object of the invention is to provide a light weight pipe wrenchwhich will be spark resistant.

A further object of the invention is te provide a pipe wrench of heat-treated forged aluminum alloy, the component parts `of the wrench being proportioned so as to have a sufliciently high yield point under proof load and so `as to resist breakage at the points where failure has most frequently occurred in prior constructions.

A still further object `of the invention is to provide a wrench of the character set forth having interchangeable jaw inserts which are of novel design and are held in a novel manner onto the wrench jaws.

The accomplishment of the foregoing and other objects of our invention not specically recited, and the invention as a whole will become apparent from the detailed description which follows when considered in connection with the accompanying drawings wherein:

Figure 1 is a front elevation of a pipe wrench embodying our invention.

Fig. 2 is a side elevation of the pipe wrench shown in Fig. l.

Fig. 3 is a section taken along the plane of the line 3-3 of Fig. 2.

Fig. 4 isa side elevation, on an enlarged scale, of the Wrench shown in Fig. 2, parts being broken away to better illustrate certain novel features of the invention.

Figs. 5, 6 and '7 are sections taken along the planes of the lines 55, I6 and I-1, respectively, of Fig. 2.

Referring to the drawings, in the Various iigures of which corresponding parts are designated by the same reference characters, the pipe Wrench may be said to consist of a handle I0 having a Xed jaw II and an integral frame I2 through which extends a threaded shank I3 of a movable jaw I4, which is adjustable relatively to the jaw I I by a nut I5 engaging the shank and supported and retained between the frame I2 and a pair of bosses I6. The jaws II and I4 are provided with replaceable jaw inserts I1 and I8, respectively. The recited elements in their cooperative relations-hip set forth are conventional in pipe Wrenches. i

The present invention is directed to a pipe wrench of the typelset forth in the preceding paragraph but formed essentially from a metal or alloy of light Weight compared to malleable iron and steel, and which light weight metal or alloy is spark resistant. Such light Weight alloysdo not have as high a yield point under proof l load as malleable iron and steel, hence, according to the present invention the various elements of the pipe wrenchhave been designed and proportioned to have yield points under proof load which compare favorably" With malleable iron and steel pipe wrenches of corresponding size. In fact, the yield points under proof load of the Wrenches made in accordance with the present invention fully `meet the specifications pertaining to heavy duty pipe wrenches made of malleable iron and steel approved by the ADirector of Procurement for use in all departments of the United States Government, see federalspecifcaat the rear of the handle beingff progressively increased height from the free end f thehandle to the frame portion I2 thereon, and the arm 20 of the H section at the front ofY thefhandlebeyond the free end thereof is of substantially uniform and less heightthan the rear armi@ at any particular H section. In carrying forward this concept, thefraine .i'2ll is yalsolproportionedfto develop a favorable tension/compressionV `ratio and-'reduced unit stresslbyhavingits top', rear andV bottom boundary wall :2L-of substantially greaterlthickness than thefbody of the frame, which` isv of substantially thesame'thicknessas the handle whereat the frame IZ- extends.V therefrom. Said thickened boundary wall-21 also preferablyextendsiforwardlyrfrom thetop-of the frame across the handle'llllto provide beneath andv adjacent :the -jawiin'sert f I l; alreinforcedsection 22 of greater width than said jaw insert. Also Yfor the :purpose Iabove .set-forth, the jaw portion of the hook jaw memberldis' reinforced by being for-medfwithagreater depth thany in-corresponding malleable iron `and vsteel pipe wrenches and-with'additional thickness of metal 23 on each face of the jaw above-andadjacent `the jaw insertVlfsaid reinforcement 23.'r forming with "the metal above said jaw-'1a substar'itiallyY in- Y verted T section. Y

' Thejawf inserts I'land i8l areE interchangeable and replaceable Aand are 'formed' of hard, Iwear resisting metal, usually steel, but where the wrench -is to be spark resistant,saidfinserts may be formedA of any suitablel'iard-spafrk resistant metal suchas a beryllium-copper alloy. Preferably the jaw inserts I l and` IB-'zftndy the jaws I I. and" I4 are 'formed iivfithfcooperating 'dovetail' mortises Aand tenons having'longitudinal axes extending parallel tothe'front face of thelwrenchl theijaw insertsfbeingV force-fitted onto' the jaws-and held against lateral' movement thereon byAA set screws '24: extending' from 1in front of Vthewrench and through side walls of the interengagingv dovetails at -a right angleto said longitudinal axes, theset screws being "formed 'with enlargedf heads fwhich are seated'within recesses -at the Afront-ofthe wrench 'jaws to llief-'flush therewith. The set screws 24` ea'cii haver-a diameter equal to at least the height ff the dovetailsand'engagesaid dovetails throughout their height; Preferably 'the diameter ofl each `set`fscrew is about 'twice `the height of the-dovetailsian'd screw-threadedly engeagelink threaded openings v25 inthe-respective jaws. there beingopen-ing'sV in the jaw inserts to accommodate the screws.

Typical dovetail practice for mating. or iinter- Y engaging dovetail mortises and tenons' provides for anrincluded angle Aof i. e., 15 at each side ofthe dovetail. 'This typical: practice,^however, does not provide the desired vclearance and/or interference of mating vdovetails of two unlike metals such as an aluminum alloyand steel, which metals havefdifferent"modulii ofV elasticity- To remedy this shortcoming, we substantially increase the included dovetail angle to between 40 and and preferably 45. The increased dovetail angle provides:

(1) An increased ratio of shear area of alu- 'minum members, since valuminum Ilias the lower allowable? unit stress of the two-metals;

2) An increased contact area, since the de- ;formation due to compressibility of aluminum is threetimes, thatof steel, and thus provides an creased area which reduces the deformation per unit of load;

" A`(3). Decreased ratio of vertical movement to horizontalfmovement, since for each unit of horizontalclearance/interference, the vertical clearance/interference is the function of the tangent ofV the dovetailfangle, and the smaller the angle the greater the vertical clearance/interference.

vvliccmding to the present invention the movable jaw is resiliently suspended in the frame I2 .byseparate Vsprings 2l and `2,8, which; .are removablyfmounted inthe :frame at thefront and rear thereof,1respectively. Preferably the spring 2lzis bowed inwardly fromend toxend longitudinally oft the `frame and'has its ends 21a 'bent rear,- wardly and seated .in recesses 29 in the frame,` to allow for flexingI of thespring, the rear wall of .the frame betweenthe'recesses ZS'beingchanneled, as indicated atf39. Thespring-I'is of iiattenedV Zk form andl isheld within a :channeix I in the'front'wall of the frameby'one end of the spring being'formed witha rearwardly bent portion 32r which .seate'in the-'rearf'end of the', hole 25-inf the Yjaw Il. Preferably the ends A28a; and 28hof the intermediate armof the Z. spring :extend in substantially `abuttingrelation `to i the top and bottomarms ofasaid spring toner-mit ready flexing ofthe-spring withoutbreaking. VIn view olf-the character and vdisposition of Ythe springs 2l1anpd 2 8 it; will be apparent thatboth springsareunder compression in alliaw shank positions and the bowedspringg'l formsacompressiblefand dynamicrocking. or pivot point 'for the movable jaw shankwhich is therebyresiliently;suspended through its full' angularv movement except at its -two eXtreme positions Yof langular movement.

IFourteeninch pipe wrenches made inl accordance with. the present invention from forged-and heat-treated `fAlcoa ST Alloy under test showed a yield point under proof load far-in excess ofthe requirements for A14malleable viron and 'steel' pipe wrenches as set forth inthe'fed- Veral specication hereinbefore referredto.

pipe. WWB-@hes mad@ il? aCCOrdaCB .With th? foregoing disclosure fully satisfy all the objects 0f ,the ini/@111910,11 as Set forth in the, opening `lstatementsof, this specification and, while we I have shown'and described a preferred embodiment of our invention, it is tobe understood that changes in the .details of. construction set lforth may be made within the range of mechanical and engineering skill without departing 'from the Spirit 0f the nVentQll ahelenafftl' Claimed- What we claimis: Y Y. Y

1- Afpipe Wrench the iaws of which are' pre'- vided with replaceable, interchangeable, wearresi'sting jaw' inserts, a'jaw and the insert therefor being formed lwith force-tted, interengag- -ingrdovetail mortises and tenons having-longitudinal axesA extending parallel to the front of i the wrench, and a lockingA pin extending-from thev front of' the `wrench-andk through sidewalls of the interengagingi. doyetailsgat;axright, angle to said longitudinal axes, said locking pin having a thickness equal to at least the height of the dovetails and engaging said dovetails substantially throughout their height.

2. A pipe wrench the jaws of which are provided With replaceable, interchangeable, wearresisting jaw inserts, a jaw and the insert therefor being formed with force-fitted, interengaging dovetail mortises and tenons having longitudinal axes extending parallel to the front of the wrench, and a locking pin extending from the front of the wrench and through side walls of the interengaging dovetails at a right angle to said longitudinal axes, said locking pin being a set-screw having a diameter approximately twice the height of the dovetails and screw-threadedly engaging threads wholly formed in the jaws.

WALTER J. JOHNSON. CARL G. ERTELL.

6 References Cited in the ille o! this patent UNITED STATES PATENTS Number Number Name Date Kasch Aug. 5, 1890 Griswold Mar. 6, 1906 Mandl Oct. 22, 1907 Vaughan Mar. 2, 1909 Dickson May 21, 1912 Coes Nov. 22, 1920 Thewes Aug. 11, 1925 Brungardt Apr. 30, 1929 Lawson Nov. 5, 1929 Kujala et al Aug. 4, 1936 Wright Mar. 5, 1940 Ingwer Jan. 27, 1942 Wilson Aug. 1, 1950 FOREIGN PATENTS Country Date Great Britain Nov. 23, 1948 France May 24, 1950 

